Conveyor dishwashers (such as a belt conveyor dishwashing machine or flight-type dishwasher) are used in the commercial area. An exemplary conveyor dishwasher is known from European Patent 0 838 190 B1. In contrast with household dishwashers in which the wash ware to be cleaned remains stationary in the machine during the cleaning process with conveyor type dishwashers the wash ware is conveyed through various zones of the conveyor dishwasher. Each zone is provided with a tank which holds the liquid sprayed in the respective zone. The conveyor dishwasher includes in particular at least one zone designed as a wash zone in which the wash ware is cleaned to remove impurities, e.g., food residues.
With known conveyor dishwashers, two factors often contribute to the total water consumption: first, the initial filling of the conveyor dishwasher in which fresh water is added to the tank of the at least one wash zone and, secondly, the final rinse during operation of the conveyor dishwasher. The final rinse liquid supplied for the final rinse runs according to the cascade principle through the entire machine. The water is kept fresh in the tanks, i.e., the concentration of impurities is kept low by constant dilution. Another effect of this supply of liquid into the tanks is that exactly as much liquid is displaced out of the tanks, i.e., enters the drain, as is supplied to the tanks.